Slide-valve-operating mechanism.



H. L. MODONALD.

SLIDE VALVE OPERATING MECHANISM.

APPLICATION mam 11.19. 1913.

Patented Oct. 21, 1913.

2 SHBETS-SHEET 1.

31mm H. L. M Dom: 1.0.

Wikuzmo H. L. MoDONALD.

SLIDE VALVE OPERATING MECEANISM.

AYYLIOATIOK mum APB. 19, 1913.

1,076,047. Patented 0ct.21,1913.

2 SHEETS-SHEET 2.

HUGH L. MCDONALD, BRIDGEPORT, CAPE BRETON, NOVA SCOTIA, CANADA:

SLIDE-VALVE-OPERATING MECHANISM.

Specification of Letters Patent.

Patented Oct. 21, 1913.

Application filed April 19, 1913. Serial No. 762,325.

anism of this character which will dispense with the usual eccentric on the engine shaft and will employ a single slide valve stem and a single guide member having a cam slot receiving the stem, there being also. a single connection between the engine pit-man and the valve stem which connection moves the valve stem in the cam slot whereby the travel is imparted to the slide valve.

A further object is to provide a novel valve stem which is so constructed as to impart the lap and lead to the slide valve.

A still further object is to provide a device of this character that will be inexpensive to manufacture and will noteasily get out of order.

With the above objects in view the invention consists of certain novel details of construction and combination of parts hereinafter fully described and claimed, it being understood thatvarious modifications may be made in the minor details of construction, within the scope of the appended claims.

In the accompanying drawings illustrating this invention: Figure 1 is a plan view, partly in horizontal section, showing the application of the invention. Fig. 2. is a side clcvatitin of the parts shown in Fig. 1. Fig. 3 is a cross sectional view on the line 3 3 Fig. 2., Fig. 4: is a cross sectional view on the lin; 4.4 Fig. 2. Fig. 5 is a diagrammatic view showing the position of the parts when the engine is on the back center. Fig. 6 is a diagrammatic view showing the position of the parts when the engine is on the forward center. Fig. 7 is a diagrammatic view showing the position of the parts when the engine is on the top quarter. Fig. 8 is a plan view showing the valve rod formed to produce lap andlead. Fig. 9 is a side elevation of the rod shown in Fig. 8. Fig. 10 is an end elevation'of the'rod shown in Fig. 8. Fig. 11 is a plan view showing a modified form of the invention. Fig. 12 is a side elevation, partly in vertical section of the parts shown in Fig. 11. Fig. 13 is a cross sectional view taken on the line 13-13 Fig. 12.

Referring now to the drawings in which like characters of reference designate similar parts, 10 designates a cylinder, 11 the pitman, and 12 the slide valve of an ordinary steam engine.

For brevity and clearncss, all parts of the engine which are not necessary to promote the disclosure of the invention are not illustrated and will not be referred to in this description.

In carrying out my invention I provide a valve rod 13 which is turnahly mounted in anopening in the slide valve 19. and is held against displacement by means of nuts 14 disposed at the ends of the valve, or otherwise. The rod is provided with a lateral offset 15 to dispose the intermediate portion 16 in close proximity to the pitman 11, the rod being offset outwardly as shown at 17 at the end of the intermediate portion to produce a crank, and then being terminally extended at a rightangle to the crank to form a gudgeon 18.

A standard 19 is disposed stationary on the engine and is provided with a cam slot 20 which extends at an angle of about forty five degrces'to the horizontal and receives the crank 17, the standard having an outwardly projecting arm 21 which is provided with an opening 22 that journals the gudgeon 1 8.

A pin 23 is threaded into the pitman and secured by means of a nut as shown, this pin carrying a forked head 2% which straddles the intermediate portion 16 of the valve rod and slides therealong during the travel of the pitinan whereby the valve rod is raised andlowered with a resultant travel of the crank 17 longitudinally in the cam slot 20 whereby the travel of the slide valve is produced.

In the ordinary cam operated slide valve, the cam on the engine shaft must be turned around and adjusted to produce the proper lead when the slide valve has a known lap. To attain this end with the above described valve rod included in the subjectmatter of this invention the valve rod must be bent up at Z) and down at (L from the center line, see Figs. 8, 9 and 10. As an example, suppose that the slide valve has inch lap then the valve rod must be bent up at 7) and down a single plane. Bending of the valve rod as above described to'produce lap and lead does not lengthen the travel of the valve, as this bending of the valve rod is analogous to turning around and adjusting the eccentric ,cam ordinarily used on engines.

In Figs. 5, 6 and 7 various positions of the slide valve and the corresponding positions of the valve rod are shown diagram matically. Fig. 5 shows the positions assumed by the valve and valve rod when the engine is on the back center, while Fig. 6 shows the positions assumed by the valve and valve rod when the engine is on the forward center. Fig. 7 shows the positions assumed by the valve and valve rod when the engine is on the top quarter. In all of these figures it will be seen that the gudgeon 18 of the rod remains constantly on the center line of the valve while the travel of the forked head of the pin carried by the pitman in its travel longitudinally of the rod moves the rod-longitudinally in the cam slot 20 and opening 21 with a resultant reciprocation of the valve.

In practice it is not necessary that the standard 19 be used as the slot 20 may be formed in the casting of the waist or centerpiece of the engine, and the angle Whichthis slot makes with the horizontal is varied to suit various lengths of valve travel. As an example, when the slide valve has a travel of three inches, the slot will be disposed at an angle of forty five degrees to the hori-' zontal while the pin 23 will have a vertical rcciprocatory movement of three inches.

In Figs. 11 to 13 inclusive a modification of the invention is shown, which modification is designed for use in connection with slide valves which have a transverse travel rather than a longitudinal travel of the cylinder.

In the modified form of the invention 25 designates the cylinder and 26 the slide valve which has a travel transversely of the cylinder. In this form of the invention the valve rod does not reciprocate so that the cam slot for this purpose is dis 'icnsed with, the valve rod merely being rocked by the up and down' motion of the pin 27 carried as of the pin carried by the pitmau, the crank arm 31 will impart. the necessary travel to the slide valve.

From the above descri ption'it will be seen that the slide valve operating mechanism constructed in accordance with my invention is extremely simple in construction, is formed of a few. parts that will not easily get out of order, and may be applied to most reciprocating engines now in use WitllOUtfBXtCD- sive alterations. .i

What is claimed, is: v

1. The combination with an ei'igine slide valve and engine pitmari, of a valve stem operatively connected to said valve, :1 pin carried by said pitman and havingia sliding connection with said stem, and a stationary cam for imparting 'reciprocatory movement to said stem during actuation of the stem by said pitman.

The combination with an engine slide valve and engine pitman, of a valve stem operatively connected to said valve, a pin carried by said pitman having a forked head loosely receiving said rod, means for jour-' naling the free end of said rod, an offset formed in said rod, and a stationary member having a slot inclined at anangle to the horizontal receiving said offset, said slot o0- acting with saidpin in imparting reciprocatory movement to said valve during travel of said pitmanf.

3. The combination-with an'engine slide valve and engine'pitman', of/a valve stem connected at one end to said slide valve and having an offset formed therein to dispose the intermediate portion of said rod in close proximity'to said pitman, a pin carried by said pitrna'n having a sliding connection with said intermediate portion of said rod, a jourhal for the free end of said rod, there being a second ofiset in said .rod parallel to the first ottset and disposed between the latter and said journal, a stationary member having an inclined cam slot receiving said second ott'set, saidslot coacting with said pin in imparting reciprocatory movement to said valve during actuation of said pitman.

4. The combination with an engine slide valve and val v0 seat and pitman, of an angularly bent rod having its intermediate portion offset from its ends and being rotatably connected at. one end to said slide valve, a

journal for the opposite end of said rod, a 

